1. Field of the Invention
The present invention relates to a vehicle cooling structure.
2. Description of the Related Art
Conventionally, in a vehicle in which a radiator for an engine or the like is accommodated in a front part of the body of the vehicle, as disclosed in Japanese Patent Unexamined Publication No. Hei. 10-324206(JP-A-10-324206), a radiator grille and a bumper grille are provided in front of the radiator not only to protect the radiator against a damage by a flying gravel but also to introduce cooling air to the radiator.
On the other hand, with a view to improving the aerodynamic performance, there has been conceived a vehicle body shape design in which the surface of a bonnet is curved so that the front part of the body of a vehicle is lowered as low as possible, and in such a design, the vertical width of a front grille (a radiator grille) which extends in a vertical direction of the body narrows. In this case, to compensate for the radiator grille that narrows due to the design, the amount of cooling air taken into through the bumper grille may be increased, but there is a limit to the opening increase while securing the function required for the bumper.
Cooling air introduced through the front grille is applied to an upper part of the radiator, while cooling air introduced through the bumper grille is applied to a lower part thereof, and therefore there is a risk that the insufficient amount of cooling air is to be applied to a central part of the radiator. If the opening through which cooling air is introduced, however, is widened, there is caused a problem that the CD value (coefficient of drag) gets worse and hence the aerodynamic performance is deteriorated.
Japanese Utility model examined Publication No. Shou. 63-15078(JP-B-63-15078U) discloses a conventional vehicle cooling structure.
As shown in FIG. 16, an engine 01 is mounted in an engine compartment which is positioned at the front part of the body of a vehicle, and a radiator 05 is mounted at the front part of the engine compartment. In addition, an under guard 011 is attached to the engine compartment at the bottom thereof for covering the engine 01 from below. In the disclosed vehicle cooling structure, an outside air intake window 012 is formed in the under guard 011.
A part of a flow of air generated when a vehicle runs or running air which passes through the radiator 05 flows along the upper surface of the under guard 011 and joins another flow of running air taken into the engine compartment through the outside air intake window 012 in the vicinity of the outside air intake window 012. The flows of running air which has so joined each other then cools an output drive shaft 03 of the engine 01.
In the aforesaid conventional technique, however, there exists a relatively large gap between the body of the vehicle and the radiator 05. If much of the running air enters the engine compartment through this gap, in other words, if there is much running air which bypasses-the radiator 05, or so-called bypassed air, the cooling efficiency of the radiator 05 is affected.
Furthermore, the flow of running air which enters the engine compartment also affects the air resistance which a vehicle receives when it is running. In general, if of the running air taken into from the front part of the vehicle bypassed running air gets more than running air passing through the radiator, the air resistance tends to increase.
Moreover, when driven in snow, if there is much bypassed running air, snow tends to be allowed to easily enter the engine compartment.
To this end, an object of the invention is to provide a cooling structure for cooling uniformly and efficiently a radiator for a water-cooled engine.
With a view to attaining the above object, according to a first aspect of the invention, there is provided a cooling structure in which an opening (3) is formed in a front bumper (1) at a position facing a lower part of a radiator (5) installed at the front part of the body of a vehicle, and in which a bumper louver (8) is provided in the opening (3) which has air duct plates (10) provided integrally in an inclined fashion so as not only to direct cooling air toward a central portion of the radiator (5) but also to shield the opening (3) when viewed from the front of the vehicle body.
According to this construction, cooling air entering the interior of the vehicle body from the opening facing the lower part of the radiator can be directed toward the central part of the radiator, and therefore, even if the opening is formed in the front bumper at the position facing the lower part of the radiator, it is possible not only to prevent the deterioration of cooling effect of the radiator but also to improve the CD value because the opening is shielded by the air duct plates when viewed from the front of the vehicle body.
In addition, a plurality of vertical furring strips (3a) are provided in the opening (3), and the bumper louver (8) has vertical bars (8a) adapted to engagedly attach to the vertical furring strips (3a) and the air duct plates (10) integrally formed so as to extend across the vertical bars (8a). The air duct plates (10) are each formed so as to have substantially V-shaped cross-sectional configurations only in the vicinity of the vertical bars (8a) and are connected to the vertical furring strips (3a) at free end portions of the substantially V-shaped cross-sectional configuration. According to this construction, the vertical bars are to be positioned on a downstream side of cooling air relative to frontal protruding ends of the air duct plates, and this improves the straightening effect on cooling air. Moreover, the deterioration in rigidity of the air duct plates 10 due to the construction in which the frontal protruding ends of the air duct plates are positioned frontward can be prevented by allowing the air duct plates to be connected to the vertical bars at the free ends of the substantially V-shaped cross-sectional configuration.
In order to cool the radiator for the water-cooled engine disposed rearward of the face of the bumper with running air introduced through the opening formed according to the first aspect of the invention, it is preferable to detachably attach to a front bulkhead left and right guide plates and a lower guide plate which are adapted to guide running air introduced through the opening to the radiator.
According to the aforesaid construction, the running air introduced through the opening can be directed more aggressively to the radiator for the water-cooled engine with the left and right guide plates and lower guide plates. This decreases the amount of the running air entering the engine compartment without passing through the radiator, or the so-called bypassed running air. Thus, the radiator can be cooled more efficiently by allowing a sufficient amount of running air to be taken into to pass through the radiator. Moreover, since there exists little bypassed running air, the air resistance the vehicle receives while running decreases, and the amount of snow penetrating into the engine compartment while running in snow also decreases.